Shoe sole having portions of different elasticity in combination with safety boot



Jan. 19, 1965 H. w. RoLLMAN 3,165,841

sHoE SOLE HAVING PORTIoNs 0F DIFFERENT ELASTICITY IN COMBINATION WITH SAFETY BooT Filed March 19, 1962 kbl ' INVENTOR HEI/vz m noLLNA/v ATTORNEY United States Patent 3,165,841 SHOE SOLE HAVING PORTIONS OF DEFERENT LASTICTY IN COMBINATION W'I'H SAFETY T Heinz W. Rollman, Waynesville, N.C., assigner to R0- Search, Inc., Waynesville-Hazelwood, N.C., a corporation of North Carolina Filed Mar. 19, 1962, Ser. No. 130,809 1 Claim. (Cl. S16- 2.5)

The invention refers to footwear, such as boots, shoes, etc., with a protective toe cap.

In the manufacture of such footwear it is customary to insert a toe cap of materials, such as steel, between the leather of the upper and the lining. In the completed shoe the edge of the toe cap rests on the upper surface of the leather sole, which is normally strong enough to take the shock of an accidental or test load.

It has been found that this shoe construction is not satisfactory when the leather sole is replaced by molded elastomeric material, such as rubber soles.

One object of the invention is to provide shoes with protective safety toe caps with elastomeric soles, which offer the comfort and other advantages of elastomeric soles while simultaneously maintaining the safety protection of leather soled footwear.

Other objects of the invention refer to the ease of manufacture of footwear with safety toe caps and molded soles.

FIGURE 1 is a longitudinal sectional View of the front portion of a shoe embodying the improved construction of the present invention.

It is desirable for footwear to use elastomeric material which has the ability to transmit forces applied in one area, such as the pressure of a pebble, to larger areas, where this pressure may be absorbed by temporary deformation of the sole material. In using such elastomeric sole material as rubber in footwear, incorporating a protective toe cap, it has been found that this quality of temporary deformation is not desirable at the toe area. When a force is applied to a steel toe cap supported by a normal elastomer compound, such as rubber, the pressure along the small area of contact between the toe cap and the rubber sole is transmitted in a manner to cause an upward bulge between the edges of the toe cap and directly beneath the highest point of the arch formed by the shape of the toe cap. This bulge decreases the available toe space. The shoe then fails to meet the specifications No. 241.1-1944 of the American Standards Association, even though the steel toe cap itself does meet the standard when tested outside the shoe.

According to the invention an elastomer soled shoe having a leather upper, lining, insole and welt with a steel safety toe cap is provided, which has the advantages of the elastomer sole in regard lto exibility, resiliency, weight, abrasion resistance and comfort without the deficiencies of elastomer soles hitherto in regard to the support of the steel safety toe cap. This is achieved by providing, in addition to the major portion of the soft sole part consisting of normal and customary elastorneric material, a special front toe portion integral with the said sole lying beneath the protective toe cap, and being coeXtensive therewith, consisting of an elastomeric compound with the ability to absorb forces applied to it rather than to transmit said forces, and resulting in a rigid sole part. The novel and unique properties of this elastomeric compound are achieved by incorporation of hydrated silica reinforcing pigments and fibrous material. These especially selected fillers interfere with the elastic crosslink network of the elastomer, thus consid- ICC Parts by weight Natural rubber Pliolite SGB (high styrene resin) 50 Hi Sil 233 35 Solka Floc (BW-40) 10 Whiting 12.5

Curatives, coloring material and protective agents 22.8

Another elastomeric compound, which has been used to produce shoes meeting the A.S.A. Standard No. Z41.1-

1944, is given below:

Parts by weight Hycar 100 X 145 100 Hi Sil 233 35 Atomite 50 Solka Floc (BW-40) l0 Curatives, coloring materials and protective agents 14.75

Another elastomeric compound, which has been used to produce shoes meeting the A.S.A. Standard No. Z4l.l- 1944, is given below:

Parts by weight Hycar 1000 X 100 HiSil 233 50 Solka Floc (BW-40) 15 Curatives, coloring materials and protective agents 14.75

The major portion of the sole is made preferably with the same basic elastomer material, but without the aforementioned silica reinforcing material and the fibrous material or substantially smaller amounts thereof. Other llers, which improve the elasticity and the comfort, such as cork granules, might be used for the major part of the sole outside of the toe cap area.

It has been found essential that not only the rim part of the toe area, which directly supports the steel toe cap, but the entire area under the toe cap should consist of the aforementioned compound.

Further, in accordance with the invention, the sole element is molded as one integral piece by iilling the sole mold with unvulcanized pieces of the special compound for the toe part and unvulcanized pieces of the customary sole compound for the remaining major part of the sole. This simultaneous molding and vulcanizing of the two compounds is of special advantage when the sole element is molded onto the shoe part and vulcanized thereto in a single operation. If desired, the Sole element might contain in the area outside of the toe area, filler material, such as porous rubber, or a porous rubber and cork compound.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

A safety boot comprising an upper, a rigid toe cap secured to the toe portion of said upper, and a sole, said sole consisting of molded elastomeric material and having a front toe portion which underlies and is coextensive with the entire area of said toe cap, said front toe portion of said elastomeric material being of con- Patented Jan. 19 1965.

3 siderably llower elasticity than the major portion of said sole, so that when force is applied to the toe cap, said front toe portion of the sole will absorb the force and resist deformation.

References Cite bythe Examiner UNITED STATES PATENTS 1,110,353 9/14 Slater 36-32 1,507,844 9/24 Mason 36--31 X 2,426,211 8/47 Heckman 36-4 2,897,610 8/59 Campagna 36--4 FOREIGNMPATENTS France. France. France. Great Britain. Great Britain. Great Britain.

JORDAN FRANKLIN, Primary Examiner.

DAVID I. NLLIAMOWSKY, FRANK I. COHEN,

Examiners. 

